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-rw-r--r--plugins/mod_compression.lua115
1 files changed, 115 insertions, 0 deletions
diff --git a/plugins/mod_compression.lua b/plugins/mod_compression.lua
new file mode 100644
index 00000000..4ff10d5a
--- /dev/null
+++ b/plugins/mod_compression.lua
@@ -0,0 +1,115 @@
+-- Prosody IM
+-- Copyright (C) 2009 Tobias Markmann
+--
+-- This project is MIT/X11 licensed. Please see the
+-- COPYING file in the source package for more information.
+--
+
+local st = require "util.stanza";
+local zlib = require "zlib";
+local pcall = pcall;
+
+local xmlns_compression_feature = "http://jabber.org/features/compress"
+local xmlns_compression_protocol = "http://jabber.org/protocol/compress"
+local compression_stream_feature = st.stanza("compression", {xmlns=xmlns_compression_feature}):tag("method"):text("zlib"):up();
+
+local compression_level = module:get_option("compression_level");
+
+-- if not defined assume admin wants best compression
+if compression_level == nil then compression_level = 9 end;
+
+compression_level = tonumber(compression_level);
+if not compression_level or compression_level < 1 or compression_level > 9 then
+ module:log("warn", "Invalid compression level in config: %s", tostring(compression_level));
+ module:log("warn", "Module loading aborted. Compression won't be available.");
+ return;
+end
+
+module:add_event_hook("stream-features",
+ function (session, features)
+ if not session.compressed then
+ -- FIXME only advertise compression support when TLS layer has no compression enabled
+ features:add_child(compression_stream_feature);
+ end
+ end
+);
+
+-- TODO Support compression on S2S level too.
+module:add_handler("c2s_unauthed", "compress", xmlns_compression_protocol,
+ function(session, stanza)
+ -- checking if the compression method is supported
+ local method = stanza:child_with_name("method")[1];
+ if method == "zlib" then
+ session.log("info", method.." compression selected.");
+ session.send(st.stanza("compressed", {xmlns=xmlns_compression_protocol}));
+ session:reset_stream();
+
+ -- create deflate and inflate streams
+ local status, deflate_stream = pcall(zlib.deflate, compression_level);
+ if status == false then
+ local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
+ session.send(error_st);
+ session:log("error", "Failed to create zlib.deflate filter.");
+ module:log("error", inflate_stream);
+ return
+ end
+
+ local status, inflate_stream = pcall(zlib.inflate);
+ if status == false then
+ local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
+ session.send(error_st);
+ session:log("error", "Failed to create zlib.deflate filter.");
+ module:log("error", inflate_stream);
+ return
+ end
+
+ -- setup compression for session.w
+ local old_send = session.send;
+
+ session.send = function(t)
+ local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync');
+ if status == false then
+ session:close({
+ condition = "undefined-condition";
+ text = compressed;
+ extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
+ });
+ module:log("error", compressed);
+ return;
+ end
+ old_send(compressed);
+ end;
+
+ -- setup decompression for session.data
+ local function setup_decompression(session)
+ local old_data = session.data
+ session.data = function(conn, data)
+ local status, decompressed, eof = pcall(inflate_stream, data);
+ if status == false then
+ session:close({
+ condition = "undefined-condition";
+ text = compressed;
+ extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
+ });
+ module:log("error", compressed);
+ return;
+ end
+ old_data(conn, decompressed);
+ end;
+ end
+ setup_decompression(session);
+
+ local session_reset_stream = session.reset_stream;
+ session.reset_stream = function(session)
+ session_reset_stream(session);
+ setup_decompression(session);
+ return true;
+ end;
+ session.compressed = true;
+ else
+ session.log("info", method.." compression selected. But we don't support it.");
+ local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
+ session.send(error_st);
+ end
+ end
+);